A device and method for synchronously realizing waste gas and wastewater purification in a sewage plant

Abstract

The application provides a device and method for simultaneously realizing purification of waste gas and wastewater in a sewage plant, which comprises a microalgae growth unit and a deep denitrification unit; the microalgae growth unit comprises a microalgae reaction tank with a closed top end, and the microalgae reaction tank comprises a growth area for culturing microalgae; the deep denitrification unit comprises a front-end biological filter tank and a rear-end biological filter tank with closed top ends; the front-end biological filter tank comprises a front-end filler area loaded with a complex bacterial community of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane-oxidizing bacteria and oxidizing sulfur Thiobacillus, and the rear-end biological filter tank comprises a rear-end filler area loaded with sulfur-iron autotrophic denitrification bacteria; due to the arrangement of the above units, the device can simultaneously realize efficient purification of sulfur-containing and other foul-smelling waste gas and greenhouse gas in a sewage plant, and can realize deep denitrification and phosphorus removal and resource utilization of the sewage.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and in particular to a device and method for purifying waste gas and waste water from a sewage treatment plant. Background Art

[0002] The wastewater from sewage treatment plants is rich in nitrogen and phosphorus sources. If the wastewater is not recycled and discharged into rivers, it will cause eutrophication of the rivers and frequent "water blooms" in the rivers. At the same time, the waste gas from sewage treatment plants contains malodorous waste gases such as sulfur and fugitive greenhouse gases. Among them, malodorous waste gases such as sulfur have a strong pungent smell and are also toxic. If not handled properly, they will pose a serious threat to the lives and safety of surrounding residents and factory workers.

[0003] Currently, the treatment methods for wastewater and waste gas from sewage treatment plants are relatively simple. For example, research on the treatment and disposal of sewage treatment plant waste gas mainly focuses on the purification of sulfur-containing odorous waste gas, while less consideration is given to the purification of fugitive greenhouse gases such as CO2, CH4, and N2O. The resource utilization of sewage treatment plant waste gas is still mostly limited to research on methane recovery and power generation. Therefore, it is of great significance to provide a device and process that can simultaneously achieve efficient purification of sulfur-containing and other odorous waste gases and greenhouse gases from sewage treatment plants, as well as coordinated deep denitrification and phosphorus removal from wastewater and resource utilization. Summary of the Invention

[0004] The present invention provides a device for simultaneously purifying waste gas and wastewater from sewage treatment plants. The device can simultaneously achieve efficient purification of sulfur-containing odorous waste gas and greenhouse gases in waste gas from sewage treatment plants, as well as coordinated deep nitrogen and phosphorus removal and resource utilization of sewage.

[0005] The present invention also provides a method for purifying waste gas and waste water from a sewage treatment plant by using the above-mentioned device for simultaneously purifying waste gas and waste water from a sewage treatment plant. The method is simple and easy to implement and can achieve good waste gas and waste water purification effects from a sewage treatment plant with the help of the above-mentioned water purification device.

[0006] In one aspect, the present invention provides a device for simultaneously purifying waste gas and wastewater in a sewage treatment plant, comprising: a microalgae growth unit and a deep denitrification unit;

[0007] The microalgae growth unit includes a microalgae reaction tank with a closed top, which is sequentially arranged from bottom to top with a first feeding area, a growth area, a microalgae collection area, and a first discharge area; the growth area includes a plurality of spaced support frames and a bio-rope filler surrounding at least a portion of the support frames; the growth area is used to cultivate microalgae; the microalgae collection area includes an algae scraper and an algae collector; the first feeding area includes a pipeline for receiving liquid and gas; the first discharge area includes a pipeline for emptying liquid and gas and a pipeline for discharging liquid and gas into the next tank body; the pipelines in the first feeding area and the first discharge area are both equipped with control valves;

[0008] The deep denitrification unit includes a front-end biofilter and a rear-end biofilter with closed tops;

[0009] The front-end biological filter is sequentially arranged with a second feed zone, a front-end filling zone, and a second discharge zone from bottom to top; the front-end filling zone is loaded with a composite bacterial community of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria, and Thiobacillus thiooxidans; the second feed zone includes a pipeline for receiving at least part of the liquid and gas discharged from the first discharge zone; the second discharge zone includes a pipeline for emptying the liquid and gas and a pipeline for discharging the liquid and gas into the next tank body; the pipelines of the second feed zone and the second discharge zone are both equipped with control valves;

[0010] The rear-end biological filter is sequentially provided with a third feed zone, a rear-end filling zone, and a third discharge zone from bottom to top; the rear-end filling zone is loaded with sulfur-iron autotrophic denitrifying bacteria, the third feed zone includes a pipeline for receiving at least part of the liquid and gas discharged from the second discharge zone; the third discharge includes a pipeline for discharging liquid and gas; and the pipelines of the third feed zone and the third discharge zone are both provided with control valves.

[0011] Furthermore, it also includes: a pressurized dissolved air unit, which includes: an air compressor, a pressurized dissolved air tank, a Y-type filter and a dissolved air releaser connected in sequence, the pressurized dissolved air tank includes a pipeline for receiving waste water, and the air compressor includes a pipeline for receiving waste gas; the dissolved air releaser includes a wastewater outlet; the wastewater outlet is connected to the pipeline of the first feeding area for receiving liquid; the pipelines of the pressurized dissolved air unit are all provided with control valves.

[0012] Furthermore, the microalgae reaction tank also includes an ultrafiltration membrane filtration component, which includes an ultrafiltration membrane and a backwashing component; the liquid discharged from the first discharge area enters the second feed area after being filtered by the ultrafiltration membrane, and the backwashing component is used to flush the ultrafiltration membrane.

[0013] Furthermore, the composite bacterial community includes heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans in a mass ratio of 4-5:3-4:3-4.

[0014] Furthermore, the front-end filling area includes, from bottom to top, a filter brick layer, a filter material supporting layer, and a quartz sand filter material layer; the composite bacterial community is arranged in the quartz sand filter material layer.

[0015] Furthermore, the rear end filling area includes a filter brick layer, a filter material supporting layer and a filter material layer from bottom to top; the filter material layer includes elemental sulfur and iron composite mineral filter material; the sulfur-iron autotrophic denitrifying bacteria are arranged in the filter material layer.

[0016] Furthermore, the second feed zone and the third feed zone are both provided with backwashing devices, which are used to backwash the front-end biological filter and the rear-end biological filter respectively.

[0017] Furthermore, it also includes: a PLC online control unit, which includes a first control unit, a second control unit, a third control unit, a fourth control unit and a fifth control unit; wherein the first control unit is arranged in the microalgae growth unit, including an electrically connected light intensity sensor, a supplementary light device and an online algae analyzer; the second control unit is arranged in the front-end biological filter, including an inlet flow online detector, a DO online monitor and a pH online monitor; the third control unit is arranged in the rear-end biological filter, including a DO online monitor, a pH online monitor, an outlet ammonia nitrogen concentration online detector and an outlet H2S concentration online detector; the fourth control unit is arranged in the pressurized dissolved air unit, electrically connected to the online algae analyzer, and automatically switches to a water inlet mode or a microalgae collection mode by receiving an electrical signal from the online algae analyzer; the fifth control unit is used to control the backwash program of the ultrafiltration membrane filtration component, the front-end biological filter and the rear-end biological filter, and automatically switches to a wastewater treatment mode, a waste gas treatment mode or a backwash mode according to a set backwash cycle.

[0018] In another aspect, the present invention provides a method for purifying waste gas and wastewater from a sewage treatment plant using the above-mentioned device, comprising the following steps:

[0019] 1) opening a control valve for a pipeline in a first feed zone for receiving liquid and gas and a control valve for draining liquid and gas, while closing a control valve for a pipeline in a second feed zone for receiving liquid and gas, introducing artificially distributed water and exhaust gas into the microalgae growth unit through the first feed zone, inoculating a certain amount of microalgae stock solution into the growth zone of the microalgae growth unit so that the initial microalgae concentration in the microalgae growth unit is 0.05 g / L, controlling the ratio of illumination to no illumination in the growth zone to be 10-12 hours:10-12 hours, and the illumination intensity to be 4000-5000 lux, and culturing until the thickness of the microalgae attached to the bio-rope filler reaches 1-3 mm and the effluent water quality is stable; wherein the artificially distributed water contains: 50-100 mg / L COD, 2-8 mg / L ammonia nitrogen, 10-20 mg / L total nitrogen, and 0.8-1.5 mg / L total phosphorus;

[0020] 2) closing the control valve of the pipeline for emptying liquid and gas in the first feeding area, opening the control valve of the pipeline for receiving liquid and gas in the second feeding area and the control valve of the pipeline for emptying liquid and gas in the second feeding area, and closing the control valve of the pipeline for receiving liquid and gas in the third feeding area at the same time, inputting the artificial water distribution and waste gas discharged from the first discharging area into the front-end biological filter through the second feeding area, inoculating the front-end filler area of ​​the front-end biological filter with a composite flora of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans, and culturing until the front-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable;

[0021] 3) closing the pipeline control valve of the second feed zone for emptying liquid and gas, opening the pipeline control valve of the third feed zone for receiving liquid and gas, inputting the artificial water and waste gas discharged from the second discharge zone into the rear-end biological filter through the third feed zone, inoculating a certain amount of sulfur-iron autotrophic denitrifying bacteria into the rear-end filler area of ​​the rear-end biological filter, and culturing until the rear-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable;

[0022] 4) By controlling the control valve of the pressurized dissolved air unit for receiving the artificial water distribution and the actual wastewater from the sewage treatment plant, the artificial water distribution entering the pressurized container tank is gradually reduced at a flow gradient of 10% to 15%, and at the same time, the actual wastewater from the sewage treatment plant is gradually increased at a flow gradient of 10% to 15% until the artificial water distribution flow is 0.

[0023] Furthermore, the method further comprises the following steps: scraping the suspended microalgae on the liquid surface of the microalgae growth unit by an algae scraper, and collecting the scraped suspended microalgae in a collecting member, so that the concentration of the suspended microalgae in the microalgae growth unit is below 0.4 g / L.

[0024] The device of the present invention can utilize the original components in waste gas and waste water to convert CO2, NH3 and N, P inorganic salts in sewage into growth substrates for microalgae, convert CH4 into electron donors for aerobic denitrifying bacteria, and convert H2S into electron donors for sulfur autotrophic denitrifying bacteria, thereby greatly saving the cost of sewage and waste gas treatment. Specifically, the present invention reduces greenhouse gas and odor emissions by introducing a microalgae growth unit and utilizing the microalgae's absorption of CO2 and NH3, while achieving the absorption of inorganic salts such as N and P in sewage. In addition, the organic matter produced by the microalgae The waste gas and oxygen can provide conditions for the growth of aerobic denitrifying bacteria in the front-end biological filter, and can oxidize the H2S in the exhaust gas into elemental S, reducing the addition of carbon sources, flocculants and other reagents in the process of deep denitrification and phosphorus removal of conventional sewage; at the same time, the front-end aerobic methane oxidation-heterotrophic denitrification-back-end anoxic autotrophic denitrification design is introduced, and a multi-stage biological denitrification filter is constructed according to the growth characteristics of functional microorganisms, which effectively improves the growth rate of various microorganisms and the degradation efficiency of pollutants, and fully combines the advantages of both autotrophic and heterotrophic denitrification to improve the denitrification efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] Figure 1 A device for simultaneously purifying waste gas and waste water from a sewage treatment plant according to a specific embodiment of the present invention;

[0027] In the figure, 1.1 - pressurized gas dissolving unit artificial water supply pipeline, 1.2 - pressurized gas dissolving unit actual wastewater supply pipeline, 1.3 - pressurized gas dissolving unit tap water supply pipeline, 1.4 - first feeding area water inlet pipe, 1.5 - first feeding area water outlet pipe, 1.6 - second feeding area wastewater distribution pipeline, 1.7 - second discharging area water outlet pipe, 1.8 - third feeding area bottom water inlet pipe, 1.9 - third discharging area water outlet pipe, 2.1 - pressurized gas dissolving unit exhaust gas inlet pipe, 2.2 - pressurized gas dissolving unit air inlet pipe, 2.3 - microalgae reaction tank top gas outlet pipe, 2.4 - second feeding area exhaust gas distribution pipeline, 2.5 - second discharging area top gas outlet pipe, 2.6 - third feeding area exhaust gas distribution pipeline, 2.7 - third discharging area top gas outlet pipe, 3.1 - air compressor, 3.2 - pressurized gas dissolving tank, 3.3 - Y-type filter, 3.4 - gas dissolving releaser, 4.1 - first feeding area, 4.2 - growth area, 4.3 - ultrafiltration membrane filtration unit, 4.4 - microalgae collection area, 4.5 - first discharging area, 4.6 - emptying pipe, 4.2.1 - immobilized biological rope filler, 4.2.2 - support steel frame, 4.2.3 - light supplementing equipment, 4.4.1 - algae scraping assembly, 4.4.2 - algae collecting hopper, 5.1 - second feeding area, 5.2 - front filler area, 5.3 - second discharging area, 5.4 - third feeding area, 5.5 - rear filler area, 5.6 - third discharging area, 5.5.1 - filter brick layer, 5.5.2 - filter material support layer, 5.5.3 - filter material layer, 6.1 - microalgae growth unit backwashing air inlet pipe, 6.2 - backwashing water inlet pipe, 6.3 - microalgae growth unit backwashing medicine inlet pipe, 6.4 - microalgae growth unit backwashing water outlet pipe, 6.5 - backwashing air inlet pipe of deep denitrification unit.

[0028] Figure 2 The figure is a schematic diagram of the principle of the device for the synchronous implementation of the purification of exhaust gas and wastewater in a sewage plant according to one specific embodiment of the present application.

[0029] The specific embodiments of the present application have been shown in the above figures, and will be described in more detail hereinafter. The figures and the textual description are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the application examples will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific direction. It is constructed and operated in a specific direction. Therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] In the first aspect, the present invention provides a device for purifying waste gas and waste water simultaneously in a sewage treatment plant. Figure 1 , describes in detail the device, which includes: a microalgae growth unit and a deep denitrification unit;

[0034] The microalgae growth unit comprises a microalgae reaction tank with a closed top, which is sequentially arranged from bottom to top with a first feed zone 4.1, a growth zone 4.2, a microalgae collection zone 4.4, and a first discharge zone 4.5. The growth zone comprises a plurality of spaced support frames and a bio-rope filler surrounding at least a portion of the support frames. The growth zone is used to cultivate microalgae, and the microalgae collection zone comprises an algae scraper and an algae collector. The first feed zone comprises a pipeline for receiving liquid and gas. The first discharge zone comprises a pipeline for emptying liquid and gas, as well as a pipeline for discharging liquid and gas into the next tank body. The pipelines in the first feed zone and the first discharge zone are both equipped with control valves.

[0035] The deep denitrification unit includes a front-end biofilter and a rear-end biofilter with closed tops;

[0036] The front-end biofilter is sequentially arranged from bottom to top with a second feed zone 5.1, a front-end filling zone 5.2, and a second discharge zone 5.3; the front-end filling zone includes a composite bacterial community of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria, and Thiobacillus thiooxidans; the second feed zone includes a pipeline for receiving at least a portion of the liquid and gas discharged from the first discharge zone; the second discharge zone includes a pipeline for emptying the liquid and gas, as well as a pipeline for discharging the liquid and gas to the next tank body; the pipelines in the second feed zone and the second discharge zone are both equipped with control valves;

[0037] The rear-end biological filter is sequentially arranged from bottom to top with a third feed zone 5.4, a rear-end filling zone 5.5, and a third discharge zone 5.6; the rear-end filling zone includes sulfur-iron autotrophic denitrifying bacteria, the third feed zone includes a pipeline for receiving at least part of the liquid and gas discharged from the second discharge zone; the third discharge includes a pipeline for discharging liquid and gas; and the pipelines in the third feed zone and the third discharge zone are both provided with control valves.

[0038] On the one hand, the above-mentioned device, by setting up a microalgae growth unit, can utilize the microalgae to absorb CO2 and NH3, thereby reducing greenhouse gas and odor emissions, and at the same time realize the absorption of inorganic salts such as N and P in sewage, thereby reducing the addition of carbon sources and flocculants and other agents in the process of deep denitrification and phosphorus removal of conventional sewage. In addition, the organic matter and oxygen produced by the photosynthesis of microalgae can provide conditions for the growth of aerobic denitrifying bacteria, and can oxidize H2S in the waste gas into elemental S; on the other hand, the above-mentioned device introduces a deep denitrification unit and constructs a multi-stage filter tank according to the growth characteristics of functional microorganisms, effectively improving the growth rate of various microorganisms and the degradation efficiency of pollutants, and fully combining the advantages of autotrophic and heterotrophic denitrification to improve the denitrification efficiency of the system.

[0039] The types of microalgae in the above algae liquid can be selected according to the resource utilization method of collecting microalgae. For example, for the development of biofuels, Chlorella, Scenedesmus, Dunaliella, and Botrytis cinerea, which have significant lipid and carbohydrate accumulation, can be used; for the preparation of feed and slow-release fertilizers, Spirulina, which has a high protein content, can be used.

[0040] It can be understood that the main function of the above-mentioned first feed area, second feed area and third feed area is to pass wastewater and / or waste gas to supply them to the growth area, front end filling area and rear end filling area respectively. Therefore, the first feed area, second feed area and third feed area correspond to the growth area, front end filling area and rear end filling area one by one and are interoperable. Moreover, the first feed area, second feed area and third feed area are respectively provided with feed ports and / or feed pipes. As for the specific positions and specifications of the specific feed ports and pipes, the present invention does not specifically limit them, and technicians can determine them based on the actual situation. Adjust according to actual conditions; similarly, the main functions of the above-mentioned first discharging area, second discharging area and third discharging area include discharging wastewater or waste gas from the growth area, front-end filling area and rear-end filling area. Therefore, the first discharging area, second discharging area and third discharging area correspond to the growth area, front-end filling area and rear-end filling area one by one and are interconnected, and the first discharging area, second discharging area and third discharging area are correspondingly provided with discharge ports and / or discharge pipes inside. As for the specific positions and specifications of the specific discharge ports and pipes, the present invention does not make any special restrictions, and technical personnel can adjust according to actual conditions.

[0041] In a specific embodiment, the first feed area includes a first water inlet pipe; the first discharge area includes a first water outlet pipe, a first air outlet pipe, a first wastewater outlet and a first waste gas outlet; the second feed area includes a first air inlet pipe and a second water inlet pipe, each of which is provided with a control valve; the first air inlet pipe is detachably connected to the first air outlet pipe, and the second water inlet pipe is detachably connected to the first first water outlet pipe; the second discharge area includes a second water outlet pipe, a second air outlet pipe, a second wastewater outlet and a second waste gas outlet; the third feed area includes a third water inlet pipe and a second air inlet pipe, the third water inlet pipe is connected to the second water outlet pipe, and the third air inlet pipe is connected to the second air outlet pipe; the third discharge area includes a third water outlet pipe and a third air outlet pipe.

[0042] Furthermore, the first water inlet pipe, the second water inlet pipe, and the third water inlet pipe are each provided with a plurality of water outlets; the first air inlet pipe and the second air inlet pipe are each provided with a plurality of air inlets.

[0043] The above-mentioned first exhaust gas outlet and the second exhaust gas outlet are connected to the waste gas collecting main pipe of the sewage treatment plant through a pipe. The above-mentioned pipe can be used as a gas bypass pipe. During the initial commissioning or when the back-end device fails, the gas can be directly discharged to the exhaust gas collecting main pipe through the outlet. In addition, the above-mentioned first wastewater outlet and the second wastewater outlet are connected to the water inlet pipe of the secondary treatment unit of the sewage treatment plant through a pipe. When the initial commissioning or the back-end device fails, the gas can be returned to the secondary treatment unit through the outlet for biochemical treatment again to ensure that the effluent from the sewage treatment plant meets the standards.

[0044] For example, the above-mentioned biological rope filler can be a BZ-S type rope-shaped biological filler, which is made of a mixture of elastic material and soft material. In a specific embodiment, the volume to surface area ratio of the BZ-S type rope-shaped biological filler can reach 5600-6500m 2 / m 3 , the filler filling volume ratio is 40%-50%.

[0045] The above-mentioned microalgae reaction pool preferably adopts a closed photobioreactor, and the bioreactor is made of glass, resin and other materials with good light transmittance; the above-mentioned front-end biological filter and rear-end biological filter can adopt a cover and seal design, and the cover and seal adopt an inverted membrane material, and an anti-corrosion coating is applied on the inside of the inverted membrane material; the air distribution pipes at the bottom of each level of filter are installed with spherical crown aerators that are resistant to aging and corrosion.

[0046] In addition, it can be understood that the aerobic denitrifying bacteria of the present invention include conventional heterotrophic nitrification and aerobic denitrification functional bacteria, such as the Indian bacterium disclosed in the invention patent CN113736700B, and functional bacteria with N2O removal ability, such as the Pseudomonas stutzeri disclosed in the invention patent CN114107136A; aerobic methane oxidizing bacteria can convert methane in the exhaust gas into CO2 and organic matter such as methanol, formaldehyde and formate, providing electron donors for aerobic denitrifying bacteria; H2S in the exhaust gas generates elemental sulfur under the action of Thiobacillus thiooxidans, providing electron acceptors for sulfur-iron autotrophic denitrifying bacteria in the rear-end biological filter. Figure 2 This is a schematic diagram of the principle of a device for a specific implementation method of the present invention for simultaneously purifying waste gas and wastewater in a sewage treatment plant;

[0047] The relevant reaction chemical formula is shown below:

[0048] In the front-end biological filter of the deep denitrification unit, aerobic methane oxidizing bacteria undergo methane oxidation reaction under the action of enzymes:

[0049] 2CH4+O2→2CH3OH(methanol)

[0050] 2CH3OH+O2→2HCHO+2H2O (formaldehyde)

[0051] CH3OH+O2→HCOOH+H2O(formic acid)

[0052] Heterotrophic nitrification-aerobic denitrification bacteria undergo heterotrophic nitrification-aerobic denitrification process under aerobic conditions:

[0053] NH4 + +O2→NO3 - +2H2O

[0054] 2NO3 -+10e - +12H + →N2+6H2O

[0055] 2NO2 - -N+6e - +8H + →N2+4H2O

[0056] N2O+2e - +2H + →N2+H2O

[0057] Sulfur oxidation occurs under the enzymatic action of Thiobacillus:

[0058] 2H2S+O2→2H2O+2S

[0059] 4HS - +O2→2H2O+4S

[0060] 2S+3O2+2H2O→2H2SO4

[0061] The sulfur-iron autotrophic denitrifying bacteria in the rear biological filter further denitrify the nitrogen on the basis of the front biological filter, and effectively utilize the sulfur in the first two reaction tanks. 2 -、HS - and S, the relevant reaction chemical formula is shown below:

[0062] S 2- Electron donor: 5S 2- +8NO3 - +8H + →5SO4 2- +4N2+4H2O

[0063] Using HS- as electron donor: 5HS - +8NO3 - +3H + →5SO4 2- +4N2+4H2O

[0064] With S as electron donor: 5S+6NO3 - +2H2O→5SO4 2- +3N2+4H +

[0065] With Fe as electron donor: 5Fe+2NO3 - +6H2O→5Fe 2+ +N2+12OH -

[0066] In a specific embodiment, the deep denitrification unit includes a biofilter with a sealed cover. A baffle is provided in the biofilter, which divides the filter into two parts, a front-end biofilter and a rear-end biofilter.

[0067] In an optional embodiment, the above-mentioned device also includes: a pressurized dissolved air unit, the pressurized dissolved air unit includes: an air compressor, a pressurized dissolved air tank, a Y-type filter and a dissolved air releaser connected in sequence, the pressurized dissolved air tank includes a pipe for receiving waste water, the air compressor includes a pipe for receiving waste gas; the dissolved air releaser includes a wastewater outlet; the wastewater outlet is connected to the pipe for receiving liquid in the first feed area; the pipes of the pressurized dissolved air unit are all provided with control valves.

[0068] It can be understood that the above-mentioned waste gas receiving pipe is mainly used to pass in the waste gas collected from the various gas collection hoods of the sewage treatment plant, and the waste gas includes but is not limited to a mixed gas of H2S, CH4, N2O, CO2 and NH3; the waste water receiving pipe is mainly used to pass in the waste water discharged from the secondary treatment unit of the sewage treatment plant.

[0069] In the present invention, all the pipes involved (including water inlet pipe, air inlet pipe, water outlet pipe, and air outlet pipe) are preferably not made of corrosion-resistant fiberglass pipes; in addition, in order to facilitate control, the liquid inlet, air inlet, air inlet, air outlet, water inlet pipe, and air inlet pipe involved in the present invention are each provided with an adjustable control valve.

[0070] In an optional embodiment, the microalgae reaction tank further comprises an ultrafiltration membrane filtration assembly, which comprises an ultrafiltration membrane and a backwashing component; the liquid (mainly wastewater) discharged from the first discharge area passes through the ultrafiltration membrane and is then input into the second feed area, and the backwashing component is used to flush the ultrafiltration membrane.

[0071] Exemplarily, the ultrafiltration membrane is in the form of a flat membrane assembly, and the backwash component of the ultrafiltration membrane filtration assembly includes a water washing system installed on the flat membrane assembly and an air washing system below; the water washing system includes a backwash water inlet pipe, a backwash drug inlet pipe and a backwash drain pipe, and the air washing system includes an air pump and an air inlet pipe.

[0072] In the above embodiment, the ultrafiltration rate can be restored by regularly backwashing the ultrafiltration membrane filtration component.

[0073] In an optional embodiment, the composite bacterial community comprises heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans in a mass ratio of 4-5:3-4:3-4;

[0074] Furthermore, the composite bacterial community includes 40 wt% of heterotrophic nitrification-aerobic denitrification bacteria, 30 wt% of aerobic methane oxidizing bacteria and 30 wt% of Thiobacillus thiooxidans.

[0075] The above strains are obtained by taking the enrichment culture of logarithmic growth phase OD 600 A bacterial suspension of 1.

[0076] In an optional embodiment, the front-end filling area includes, from bottom to top, a filter brick layer, a filter material supporting layer, and a quartz sand filter material layer; the composite bacterial community is arranged in the quartz sand filter material layer.

[0077] For example, the filter brick layer adopts T-shaped air-water distribution HDPE filter brick; the filter material supporting layer is paved with 5 kinds of graded pebbles, the particle size of the pebbles is 16 to 37.5 mm, and the particle size is graded from small to large from top to bottom, with a total thickness of about 450-500 mm; the particle size of the quartz sand filter material layer is 2-4 mm, and the height of the quartz sand filter material layer is 2.5 m.

[0078] In an optional embodiment, the rear end filling area includes a filter brick layer, a filter material supporting layer and a filter material layer in order from bottom to top; the sulfur-iron autotrophic denitrifying bacteria are arranged in the filter material layer.

[0079] For example, the filter brick layer adopts T-shaped air-water distribution HDPE filter brick; the filter media supporting layer is paved with 5 kinds of graded pebbles, the particle size of the pebbles is 16 to 37.5 mm, and the particle size is graded from small to large from top to bottom, with a total thickness of about 450-500 mm; the filter media of the filter media layer includes composite minerals of elemental sulfur and iron, the particle size of the filter media is 4-6 mm, and the height of the filter media layer is 2.5 m.

[0080] The above-mentioned composite mineral of elemental sulfur and iron can be a conventional composite mineral of elemental sulfur and iron, for example, a composite mineral with a particle size of 3-8 mm and a specific gravity of elemental sulfur and iron of 1.12-1.15.

[0081] In an optional embodiment, the second feed zone and the third feed zone are both provided with backwashing devices, for flushing the front-end biological filter and the rear-end biological filter, respectively.

[0082] Illustratively, the second feed zone is provided with a first backwash device, and the third feed zone is provided with a second backwash device. The first backwash device includes a first backwash water inlet pipe and a first backwash air inlet pipe. The first backwash water inlet pipe also serves as the water inlet pipe at the bottom of the front-end biological filter, and the first backwash air inlet pipe also serves as the air inlet pipe at the bottom of the front-end biological filter. The second backwash device includes a second backwash water inlet pipe and a second backwash air inlet pipe. The second backwash water inlet pipe also serves as the water inlet pipe at the bottom of the rear-end biological filter, and the second backwash air inlet pipe also serves as the air inlet pipe at the bottom of the rear-end biological filter. The first backwash device and the second backwash device may be the same or different.

[0083] Wherein, the above embodiments can periodically perform automatic backwash of the denitrification filter during operation of the front-end biological filter and the back-end biological filter to restore the filtration performance thereof.

[0084] In an optional embodiment, further comprising: a PLC online control unit (Programmable Logic Control Unit), which comprises a first control unit, a second control unit, a third control unit, a fourth control unit and a fifth control unit; wherein the first control unit is arranged in the microalgae growth unit and comprises an electrically connected light intensity sensor, a light supplementing device and an online algae analyzer; the second control unit is arranged in the front-end biological filter and comprises an air inlet flow online detector, a DO (dissolved oxygen) online monitor and a pH online monitor; the third control unit is arranged in the back-end biological filter and comprises a DO online monitor, a pH online monitor, an ammonia nitrogen concentration online detector and an H2S concentration online detector; the fourth control unit is arranged in the pressurized dissolved gas unit and is electrically connected with the online algae analyzer, and automatically switches to the water inlet mode or the microalgae collection mode by receiving the electric signal of the online algae analyzer; and the fifth control unit is used to control the backwash program of the ultrafiltration membrane filtration assembly, the front-end biological filter and the back-end biological filter, and automatically switches to the wastewater, waste gas treatment mode or the backwash mode through a set backwash period.

[0085] Exemplarily, the light supplementing device can adopt a water-immersed algae cultivation special light source, such as a T5 fluorescent daylight lamp or a 360° LED light source, which is vertically fixed on the support frame and is isolated by a quartz glass tube.

[0086] It can be understood that the PLC online control unit includes but is not limited to the first control unit, the second control unit, the third control unit, the fourth control unit and the fifth control unit, and corresponding control units can also be arranged in all working units of the device to realize the full-automatic purification of the waste water and waste gas of the sewage plant; the fourth control unit can further comprise a liquid online concentration meter and an electromagnetic flow meter on the wastewater inlet pipe, a gas online concentration meter and a pneumatic regulating valve on the waste gas inlet pipe, a float ball type liquid level controller, a pressure gauge and a safety valve on the pressurized container tank, the liquid online concentration meter and the gas online concentration meter are used to detect the concentration of the liquid and gas introduced into the liquid inlet and the gas inlet; the electromagnetic flow meter and the pneumatic regulating valve are respectively used to control the flow of the liquid and gas introduced into the liquid inlet and the gas inlet; and the float ball type liquid level controller, the pressure gauge and the safety valve are used to control the pressure of the pressurized dissolved gas tank.

[0087] It can be understood that the pressurized dissolved gas unit of the present application can be automatically switched to the water inlet mode and the microalgae collection mode by the PLC control system. In the water inlet mode, waste gas is introduced into the gas inlet, and the control valve on the pressurized tank is automatically adjusted according to the dissolved oxygen concentration in the biological filter and the waste gas outlet concentration to control the water inlet dissolved oxygen concentration of the rear-end biological filter to be below 0.5 mg / L and to ensure that H2S and NH3 in the waste gas meet the emission standards. In the microalgae collection mode, the liquid pipeline valve and the gas pipeline valve of the first discharge area to the next pool body are closed, the tap water inlet valve of the pressurized dissolved gas unit, the air inlet valve of the pressurized dissolved gas unit, the valve on the reactor top gas outlet pipeline connected to the outside, and the water outlet valve of the ultrafiltration membrane filtration system are opened, the gas float time is adjusted by the microalgae online analyzer monitoring data and the PLC control system, the microalgae concentration in the reactor is controlled to be below 0.4 mg / L, and the pressure range is adjusted to 0.25-0.4 MPa by the automatic control valve on the pressurized tank. The micro-nano bubbles in this mode are 20-50 μm.

[0088] In a second aspect, the present application provides a method for purifying waste gas and wastewater of a sewage plant by using the device described above, comprising the following steps:

[0089] 1) Open the control valves of the pipes for receiving liquid and gas and the pipes for discharging liquid and gas in the first feeding area, and close the control valves of the pipes for receiving liquid and gas in the second feeding area, introduce artificial water and waste gas into the microalgae growth unit through the first feeding area, inoculate a certain amount of microalgae stock solution into the growth area of the microalgae growth unit, so that the initial microalgae concentration in the microalgae growth unit is 0.05 g / L, the light and dark time ratio of the growth area is controlled to be 10-12 h:10-12 h, the light intensity is 4000-5000 lux, and the culture is carried out until the thickness of the microalgae attached to the biological rope filler reaches 1-3 mm, and the effluent quality is stable; wherein the artificial water comprises: 50-100 mg / L of COD, 2-8 mg / L of ammonia nitrogen, 10-20 mg / L of total nitrogen, and 0.8-1.5 mg / L of total phosphorus;

[0090] 2) Close the control valves of the pipes for discharging liquid and gas in the first feeding area, open the control valves of the pipes for receiving liquid and gas and the pipes for discharging liquid and gas in the second feeding area, and close the control valves of the pipes for receiving liquid and gas in the third feeding area, the artificial water and waste gas discharged from the first discharge area are input into the front-end biological filter through the second feeding area, and the complex microbial community of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methanotrophic bacteria, and sulfur-oxidizing Thiobacillus is inoculated into the front-end filler area of the front-end biological filter, and the culture is carried out until the microorganisms with a thickness of 0.3-0.5 mm are attached to the front-end filler area, and the effluent quality is stable;

[0091] 3) Close the pipe control valve of the second feeding area to exhaust the liquid and gas, open the pipe control valve of the third feeding area to receive the liquid and gas, the artificial water and waste gas discharged from the second discharging area are input into the back-end biological filter tank through the third feeding area, inoculate a certain amount of sulfur-iron autotrophic denitrifying bacteria into the back-end filling area of the back-end biological filter tank, and culture until the microorganisms with a thickness of 0.3-0.5 mm are attached to the back-end filling area, and the effluent water quality is stable;

[0092] 4) By controlling the pipe control valve of the pressurized dissolved gas unit to receive the artificial water and the actual waste water of the sewage plant, gradually reduce the artificial water input into the pressurized container tank at a flow gradient of 10%-15%, and gradually increase the actual waste water input at a flow gradient of 10%-15% until the artificial water flow is 0.

[0093] In the above method, the degree of purification of the waste gas and waste water of the sewage plant can be: the removal rate of H2S in the exhaust gas is above 85%, the removal rate of NH3 is above 90%, the removal rate of CH4 is above 60%, the removal rate of N2O is above 50%, the removal rate of CO2 is above 65%, and the removal rate of TN in the filter tank effluent is above 85%.

[0094] The stable effluent water quality can be understood as that the mass concentration of COD, total nitrogen, total phosphorus and the like contained in the effluent water fluctuates by no more than 10%, and exemplarily, whether the effluent water quality is stable can be judged according to the method comprising the following processes:

[0095] Randomly select two time points within 24 hours a day, take a certain amount of effluent water in a clean container, and obtain the mass concentration of COD, total nitrogen and total phosphorus in the water quality sample by analysis, then repeat the above operation for 11 days, if the mass concentration of COD, total nitrogen and total phosphorus in the obtained water quality sample is not more than 10% different from each other, it is considered that the effluent water quality is stable.

[0096] In a specific embodiment, in step 1), the thickness of the microalgae attached to the biological rope filling is 1-3 mm, and / or in step 2), the thickness of the microorganisms attached to the front-end filling area is 3-5 mm, and / or in step 3), the thickness of the microorganisms attached to the back-end filling area is 3-5 mm.

[0097] In a specific embodiment, the method further comprises the following steps: scraping the suspended microalgae on the liquid surface of the microalgae growth unit by the algae scraping member, and collecting the scraped suspended microalgae in the collection member, so that the concentration of the suspended microalgae in the microalgae growth unit is below 0.4 g / L.

[0098] In a specific embodiment, the light supplementing device is turned on when the intensity of the daylight is insufficient during the day, and the start and stop of the power supply, the light time and intensity can be adjusted by the light intensity sensor monitoring data and the PLC control system.

[0099] The present invention is described in detail below with reference to specific embodiments:

[0100] Example 1

[0101] This example provides a waste gas and waste water purification device for a sewage treatment plant, combined with Figure 1 The purification device is described in detail, including: a pressurized dissolved air unit, a microalgae growth unit, a deep denitrification unit, a backwash system, and an online monitoring unit. The entire device is sealed with a lid, and each unit is equipped with an online monitoring device, which can be controlled online by an automatic control system.

[0102] The pressurized air dissolving unit comprises an air compressor (3.1), a pressurized air dissolving tank (3.2), a Y-type filter (3.3) and an air dissolving releaser (3.4), the front end of which is connected to the artificial water distribution inlet pipe (1.1) of the pressurized air dissolving unit, the actual wastewater inlet pipe (1.2) of the pressurized air dissolving unit, the tap water inlet pipe (1.3) of the pressurized air dissolving unit, the waste gas inlet pipe (2.1) and the air inlet pipe (2.2), specifically, the artificial water distribution inlet pipe (1.1) of the pressurized air dissolving unit, the actual wastewater inlet pipe (1.2) of the pressurized air dissolving unit and the tap water inlet pipe (1.3) of the pressurized air dissolving unit are connected to the inlet at the top of the pressurized air dissolving tank (3.2), and the connecting pipes are connected. A wastewater online concentration meter and an electromagnetic flowmeter are installed; the air inlet pipes (2.1, 2.2) are connected to the waste gas inlet of the air compressor (3.1), and a gas online concentration meter and a pneumatic regulating valve are installed between the air inlet pipes (2.1, 2.2) and the air compressor (3.1); the air compressor (3.1) is connected to the pressurized dissolved gas tank (3.2) through a pipeline; a float-type liquid level controller, a pressure gauge and a safety valve are installed at the top of the pressurized dissolved gas tank (3.2); an outlet pipe is provided at the bottom; a Y-type filter (3.3) and a dissolved gas releaser (3.4) are connected to the outlet pipe, and the outlet pipe is connected to the water inlet pipe (1.4) of the first feeding area inside the microalgae growth system;

[0103] The microalgae growth unit comprises a microalgae reaction pool with a closed top, wherein the microalgae reaction pool is provided with a first feeding area (4.1), a growth area (4.2), an ultrafiltration membrane filtration unit (4.3), a microalgae collection area (4.4) and a first discharge area (4.5) in sequence from top to bottom; the first feeding area is located at the bottom end of the microalgae reactor, the water inlet is located on the left side of the pool wall, the water inlet is connected to the water inlet pipe (1.4), and the water inlet pipe (1.4) is used as a wastewater inlet pipe and a microalgae flotation collection inlet pipe at the same time; the growth area (4.2) is located in the first feeding area (4 .1), the growth area (4.2) is provided with immobilized biological rope filler (4.2.1), a supporting steel frame (4.2.2), a light intensity sensor and an online algae analyzer, and a light supplement device (4.2.3) is installed on the supporting steel frame; the ultrafiltration membrane filtration unit (4.3) is located in the upper right of the microalgae reaction tank, including an MBR flat membrane assembly and a backwash system, the backwash system including a water washing system installed on the flat membrane assembly and an air washing system below; the water washing system includes a backwash water inlet pipe (6.2), a backwash The drug inlet pipe (6.3) and the backwash drain pipe (6.4) are provided; the air washing system includes an air pump and a backwash air inlet pipe (6.1); the microalgae collection area is located at the top of the supporting steel frame (4.1.2), including an algae scraping component (4.4.1) located on the pool surface and an algae collecting bucket (4.4.2) on the left side; the first discharge area (4.5) includes an air outlet located at the center of the top of the microalgae reaction tank and a water outlet located at the end of the outlet pipe of the ultrafiltration membrane filtration system, the air outlet is connected to the air outlet pipe (2.3) at the top of the microalgae reaction tank, and one end of the air outlet pipe is connected to the depth The second feed zone waste gas distribution pipe (2.4) of the denitrification unit is connected, and the other end is connected to the waste gas collection main of the sewage treatment plant. An air pump and a gas flow meter are installed on the outlet pipe; one end of the water outlet is connected to the outlet pipe of the ultrafiltration membrane filtration system, that is, the first feed zone outlet pipe (1.5), and the outlet pipe (1.5) is connected to the liquid emptying pipe and the deep denitrification unit inlet pipe through a three-way structure; the outlet pipe is sequentially arranged with a pressure transmitter, a water production pump, an outlet flow meter and an exhaust valve; an emptying pipe (4.6) is provided at the bottom of the microalgae reaction tank.

[0104] The deep denitrification unit comprises a biofilter with a closed top, wherein a baffle divides the biofilter into two parts, a front-end biofilter and a rear-end biofilter, from the middle. The front-end biofilter is provided with a second feed zone (5.1), a front-end filler zone (5.2) and a second discharge zone (5.3) in sequence from bottom to top; the second feed zone (5.1) is located at the bottom of the biofilter and is provided with a waste gas distribution pipe (2.4) connected to the microalgae growth unit outlet pipe (2.3); the waste gas distribution pipe (2.4) is connected to the backwash inlet pipe (6.5) through a three-way structure and is also used as a backwash distribution pipe in the backwash mode; the second feed zone is also provided with a wastewater distribution pipe (1.6), which is laid above the distribution pipe and is connected to the microalgae growth unit outlet pipe (1.5) and the backwash inlet pipe through a three-way structure and is also used as a backwash distribution pipe in the backwash mode. The biofilter is provided with an emptying pipe at the bottom. When backwashing is performed, wastewater from the backwashing water inlet pipe (6.2) is discharged from the emptying pipe. The packing area (5.2) is located above the water inlet area and includes, from bottom to top, a filter brick layer, a filter material supporting layer, and a quartz sand filter material layer. The second discharge area (5.3) includes a water outlet area and a gas outlet area. The water outlet area is located above the packing layer. The front-end biofilter enters the third feed area water inlet pipe (1.8) at the bottom of the rear-end biofilter through the water outlet pipe (1.7) on the upper part of the baffle. The gas outlet area is located above the water outlet area and is provided with a gas outlet located at the center of the top of the front-end biofilter. The gas outlet is connected to a gas outlet pipe (2.5) and a waste gas one-way valve in sequence. One end of the gas outlet pipe (2.5) is connected to the waste gas distribution pipe (2.6) of the rear-end biofilter, and the other end is connected to the waste gas collection main of the sewage treatment plant. The gas outlet pipe at the other end of the rear-end biofilter is connected to the waste gas collection main of the sewage treatment plant.

[0105] The back-end biological filter is provided from bottom to top with a third feeding area (5.4), a back-end filler area (5.5), and a third discharging area (5.6); the third feeding area includes an air inlet area and a water inlet area, the air inlet area is located at the bottom end of the biological filter, and is provided with a waste gas distribution pipeline (2.6) connected with the air outlet pipe of the front-end biological filter, the waste gas distribution pipeline (2.6) is used as a backwashing distribution pipeline at the same time in the backwashing mode; the water inlet area is provided with a waste water distribution pipeline (1.8) used as a backwashing water distribution pipeline at the same time in the backwashing mode, and is provided with an emptying pipe at the bottom of the biological filter; the filler area (5.5) is located above the water inlet area and includes, from bottom to top, a filter brick layer (5.5.1), a filter material supporting layer (5.5.2), and a filter material layer (5.5.3); the third discharging area includes a water outlet area and an air outlet area, the water outlet area is located above the filter material layer, and is provided with a water outlet pipe (1.9) on the right side wall of the pool wall; the air outlet area is located above the water outlet area, is provided with an air outlet located at the top center, is provided with a demister, and is sequentially connected with an air outlet pipe (2.7) and a waste gas one-way valve, the air outlet pipe (2.7) is connected with a waste gas collection main pipe of the sewage plant, and a gas online concentration and gas flow meter is installed on the air outlet pipe.

[0106] The front-end filler area includes, from bottom to top, a filter brick layer, a filter material supporting layer, and a quartz sand filter material layer with a height of 1.3 m; the filter brick layer adopts T-shaped gas and water distribution HDPE filter bricks; the filter material supporting layer is paved with five kinds of graded distribution of pebbles, and has a total thickness of about 450-500 mm; the quartz sand has a particle size of 2-4 mm; and a composite microbial group is arranged in the quartz sand filter material layer; the composite microbial group includes 40% of heterotrophic nitrification-aerobic denitrification bacteria, 30% of aerobic methane-oxidizing bacteria, and 30% of sulfur-oxidizing thiobacillus; the heterotrophic nitrification-aerobic denitrification bacteria are composed of 30% of Pseudomonas, 30% of Delftia, and 20% of Acinetobacter, and 20% of Bacillus cereus, which are screened from the sewage plant secondary sedimentation tank sludge with a volume fraction of 30%; the aerobic methane-oxidizing bacteria are composed of 50% of Methylocystis and 50% of Klossiella, which are screened from the sewage plant secondary sedimentation tank sludge with a volume fraction of 50%; and the quartz sand has a particle size of 2-4 mm.

[0107] The rear-end filling area includes, from bottom to top, a filter brick layer, a filter media support layer with a height of 450-500mm, and a filter media layer with a height of 2.5m; the filter brick layer adopts T-shaped air-water distribution HDPE filter bricks, the filter media support layer is paved with 5 kinds of graded pebbles, the filter media of the filter media layer includes composite minerals of elemental sulfur and iron, and sulfur-iron autotrophic denitrifying bacteria are arranged in the filter media layer. The sulfur-iron autotrophic denitrifying bacteria are a composite bacterial group with denitrifying Thiobacillus, Thiobacillus thiooxidans, Thiobacillus thioreductans, Thiobacillus ferrooxidans, Citrobacter freundii, etc. as the main functional bacterial genera, which are obtained by domestication using the sludge from the secondary sedimentation tank of the sewage treatment plant as the bacterial source. Among them, the particle size of the quartz sand is 2-4mm, and the particle size of the filter media is 4-6mm.

[0108] Comparative Example 1

[0109] The same as Example 1, except that the composite bacterial community includes 50% aerobic methane oxidizing bacteria and 50% Thiobacillus thiooxidans.

[0110] Comparative Example 2

[0111] The same as Example 1, the only difference is that the filter material of the filter layer in the rear filler area is replaced with the same quartz sand filter material as that in the front biological filter.

[0112] Test Example 1

[0113] The purification devices of Example 1, Comparative Example 1 and Comparative Example 2 are used to purify waste gas and wastewater from sewage treatment plants. The waste gas comes from waste gas collected by gas collecting hoods, biochemical pools, sedimentation tanks, sludge storage tanks and other sewage treatment plant structures. The main components and contents include: CO2 concentration 9-15g / m 3 , hydrogen sulfide 11-32 mg / m 3 , ammonia 5-15mg / m 3 , methane 16-30mg / m 3 , nitrous oxide 0.4-1mg / m 3 Artificial water distribution was used to simulate actual wastewater from a sewage treatment plant to ensure that the two wastewater compositions were essentially the same. Specifically, the main components and contents included: COD concentration 50-100 mg / L, ammonia nitrogen 2-8 mg / L, total nitrogen 10-20 mg / L, and total phosphorus 0.8-1.5 mg / L. The purification process included the following steps:

[0114] 1) opening a control valve of a pipeline for receiving liquid and gas in a first feed zone and a control valve of a pipeline for draining liquid and gas, and simultaneously closing a control valve of a pipeline for receiving liquid and gas in a second feed zone, introducing artificial water and exhaust gas into the microalgae growth unit through the first feed zone, inoculating a certain amount of microalgae stock solution into the growth zone of the microalgae growth unit so that the initial microalgae concentration in the microalgae growth unit is 0.05 g / L, controlling the ratio of light and no light duration in the growth zone to 10-12 hours:10-12 hours, and the light intensity to 4000-5000 lux, and culturing until the thickness of the microalgae attached to the bio-rope filler reaches 1-3 mm, and the effluent water quality is stable;

[0115] 2) closing the control valve of the first feed zone for emptying the liquid and gas pipeline, opening the control valve of the second feed zone for receiving the liquid and gas pipeline and the control valve of the second feed zone for emptying the liquid and gas pipeline, and at the same time closing the control valve of the third feed zone for receiving the liquid and gas pipeline, the artificial water and waste gas discharged from the first discharge zone are input into the front-end biological filter through the second feed zone, and the composite flora of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans is inoculated into the front-end filler area of ​​the front-end biological filter, and culturing until the front-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable;

[0116] 3) closing the control valve of the pipeline for emptying liquid and gas in the second feeding area, opening the control valve of the pipeline for receiving liquid and gas in the third feeding area, inputting the artificial water and waste gas discharged from the second discharging area into the rear-end biological filter through the third feeding area, inoculating a certain amount of sulfur-iron autotrophic denitrifying bacteria into the rear-end filler area of ​​the rear-end biological filter, and culturing until the rear-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable;

[0117] 4) By controlling the control valve of the pressurized dissolved air unit for receiving the artificial water distribution and the actual wastewater from the sewage treatment plant, the artificial water distribution entering the pressurized container tank is gradually reduced at a flow gradient of 10% to 15%, and at the same time, the actual wastewater from the sewage treatment plant containing dissolved waste gas is gradually increased at a flow gradient of 10% to 15% until the artificial water distribution flow is 0.

[0118] 5) When the transmembrane pressure difference of the ultrafiltration membrane filtration unit of the microalgae reaction tank is lower than the set minimum limit of 0.3 bar or the membrane flux is lower than the set minimum limit of 40 L / (m2h), the backwash mode is activated, the pressure range is adjusted to 0.25-0.4 MPa by the automatic control valve on the pressurized tank, and the flotation time is adjusted by monitoring data of the microalgae online analyzer and the PLC control system so that the concentration of suspended microalgae on the liquid surface of the microalgae growth unit is within the range of 0.4 g / L; the suspended microalgae on the liquid surface of the microalgae growth unit are scraped by the algae scraper and the scraped suspended microalgae are collected in the collection unit.

[0119] Effect comparison:

[0120] In the device of Example 1, after step 3) has been running for 40 days, the exhaust H2S treatment rate is stable at 90% to 94%, the NH3 treatment rate is stable at 92% to 98%, the CH4 removal rate is stable at 60% to 66%, the N2O removal rate is stable at 48% to 57%, the CO2 removal rate is stable at 65% to 75%, and the effluent TN removal rate is stable at 82% to 89%;

[0121] Comparative Example 1: Step 3) After 40 days of operation, the exhaust H2S treatment rate reached 90%-94%, the NH3 treatment rate reached 55%-70%, the CH4 removal rate reached 40-50%, the N2O removal rate reached 8%-14%, the CO2 removal rate reached 68%-79%, and the effluent TN removal rate reached 50-60%.

[0122] Comparative Example 2: Step 3) After 40 days of operation, the exhaust H2S treatment rate reached 42%-59%, the NH3 treatment rate reached 90%-95%, the CH4 removal rate reached 60%-65%, the N2O removal rate reached 50%-56%, the CO2 removal rate reached 35%-47%, the effluent TN removal rate reached 40-48%, and the effluent contained a small amount of S elemental and S 2- .

[0123] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof, which is limited only by the appended claims.

Claims

1. A device for purifying waste gas and waste water from a sewage treatment plant simultaneously, characterized in that: include: microalgae growth unit and deep denitrification unit; The microalgae growth unit includes a microalgae reaction tank with a closed top, which is sequentially arranged from bottom to top with a first feeding area, a growth area, a microalgae collection area, and a first discharge area; the growth area includes a plurality of spaced support frames and a bio-rope filler surrounding at least a portion of the support frames; the growth area is used to cultivate microalgae; the microalgae collection area includes an algae scraper and an algae collector; the first feeding area includes a pipeline for receiving liquid and gas; the first discharge area includes a pipeline for emptying liquid and gas and a pipeline for discharging liquid and gas into the next tank body; the pipelines in the first feeding area and the first discharge area are both equipped with control valves; The deep denitrification unit includes a front-end biofilter and a rear-end biofilter with closed tops; The front-end biological filter is sequentially arranged with a second feed zone, a front-end filling zone, and a second discharge zone from bottom to top; the front-end filling zone is loaded with a composite bacterial community of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria, and Thiobacillus thiooxidans; the second feed zone includes a pipeline for receiving at least part of the liquid and gas discharged from the first discharge zone; the second discharge zone includes a pipeline for emptying the liquid and gas and a pipeline for discharging the liquid and gas into the next tank body; the pipelines of the second feed zone and the second discharge zone are both equipped with control valves; The rear-end biological filter is sequentially arranged with a third feed zone, a rear-end filling zone and a third discharge zone from bottom to top; the rear-end filling zone is loaded with sulfur-iron autotrophic denitrifying bacteria, the third feed zone includes a pipeline for receiving at least part of the liquid and gas discharged from the second discharge zone; the third discharge zone includes a pipeline for discharging liquid and gas; the pipelines of the third feed zone and the third discharge zone are both provided with control valves.

2. The device according to claim 1, characterized in that Also includes: A pressurized dissolved air unit, comprising: an air compressor, a pressurized dissolved air tank, a Y-type filter and a dissolved air releaser connected in sequence; the pressurized dissolved air tank includes a pipeline for receiving waste water, the air compressor includes a pipeline for receiving waste gas; the dissolved air releaser includes a waste water outlet; the waste water outlet is connected to a pipeline in the first feed area for receiving liquid; the pipelines of the pressurized dissolved air unit are all provided with control valves.

3. The device according to claim 2, characterized in that The microalgae reaction tank further includes an ultrafiltration membrane filtration component, which includes an ultrafiltration membrane and a backwashing component. The liquid discharged from the first discharge area is filtered by the ultrafiltration membrane and then enters the second feed area. The backwashing component is used to flush the ultrafiltration membrane.

4. The device according to claim 1, characterized in that The composite bacterial community comprises heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans in a mass ratio of 4-5:3-4:3-4.

5. The device according to claim 4, characterized in that The front-end filling area includes a filter brick layer, a filter material supporting layer and a quartz sand filter material layer in sequence from bottom to top; the composite bacterial community is arranged in the quartz sand filter material layer.

6. The device according to claim 1, characterized in that The rear end filling area includes a filter brick layer, a filter material supporting layer and a filter material layer in order from bottom to top; the filter material layer includes elemental sulfur and iron composite mineral filter material; the sulfur-iron autotrophic denitrifying bacteria are arranged in the filter material layer.

7. The device according to claim 3, characterized in that The second feed zone and the third feed zone are both provided with backwashing devices, which are used to backwash the front-end biological filter and the rear-end biological filter respectively.

8. The device according to claim 7, characterized in that Also includes: A PLC online control unit includes a first control unit, a second control unit, a third control unit, a fourth control unit and a fifth control unit; wherein the first control unit is arranged in the microalgae growth unit, including an electrically connected light intensity sensor, a supplementary light device and an online algae analyzer; the second control unit is arranged in the front-end biological filter, including an inlet flow online detector, a DO online monitor and a pH online monitor; the third control unit is arranged in the rear-end biological filter, including a DO online monitor, a pH online monitor, an outlet ammonia nitrogen concentration online detector and an outlet H2S concentration online detector; the fourth control unit is arranged in the pressurized dissolved air unit, electrically connected to the online algae analyzer, and automatically switches to a water inlet mode or a microalgae collection mode by receiving an electrical signal from the online algae analyzer; the fifth control unit is used to control the backwashing procedures of the ultrafiltration membrane filtration component, the front-end biological filter and the rear-end biological filter, and automatically switches to a wastewater, waste gas treatment mode or a backwashing mode according to a set backwashing cycle.

9. A method for purifying waste gas and waste water from a sewage treatment plant using the device for simultaneously purifying waste gas and waste water from a sewage treatment plant according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) opening a control valve for a pipeline in a first feed zone for receiving liquid and gas and a control valve for draining liquid and gas, while closing a control valve for a pipeline in a second feed zone for receiving liquid and gas, introducing artificially distributed water and exhaust gas into the microalgae growth unit through the first feed zone, inoculating a certain amount of microalgae stock solution into the growth zone of the microalgae growth unit so that the initial microalgae concentration in the microalgae growth unit is 0.05 g / L, controlling the ratio of illumination to no illumination in the growth zone to be 10-12 hours:10-12 hours, and the illumination intensity to be 4000-5000 lux, and culturing until the thickness of the microalgae attached to the bio-rope filler reaches 1-3 mm and the effluent water quality is stable; wherein the artificially distributed water contains: 50-100 mg / L COD, 2-8 mg / L ammonia nitrogen, 10-20 mg / L total nitrogen, and 0.8-1.5 mg / L total phosphorus; 2) closing the pipeline control valve for emptying liquid and gas in the first feeding area, opening the control valve of the second feeding area for receiving liquid and gas pipeline and the pipeline control valve for emptying liquid and gas in the second feeding area, and closing the pipeline control valve for receiving liquid and gas in the third feeding area at the same time, inputting the artificial water and waste gas discharged from the first discharging area into the front-end biological filter through the second feeding area, inoculating the front-end filler area of ​​the front-end biological filter with a composite flora of heterotrophic nitrification-aerobic denitrification bacteria, aerobic methane oxidizing bacteria and Thiobacillus thiooxidans, and culturing until the front-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable; 3) closing the pipeline control valve of the second feed zone for emptying liquid and gas, opening the pipeline control valve of the third feed zone for receiving liquid and gas, inputting the artificial water and waste gas discharged from the second discharge zone into the rear-end biological filter through the third feed zone, inoculating a certain amount of sulfur-iron autotrophic denitrifying bacteria into the rear-end filler area of ​​the rear-end biological filter, and culturing until the rear-end filler area is attached with microorganisms with a thickness of 0.3-0.5 mm and the effluent water quality is stable; 4) By controlling the valves of the pipelines of the pressurized dissolved air unit for receiving artificial water distribution and actual wastewater from the sewage treatment plant, the artificial water distribution entering the pressurized container tank is gradually reduced at a flow gradient of 10% to 15%, and at the same time, the actual wastewater from the sewage treatment plant is gradually increased at a flow gradient of 10% to 15% until the artificial water distribution flow is 0.

10. The method according to claim 9, characterized in that The following steps are also included: The suspended microalgae on the liquid surface of the microalgae growth unit is scraped by an algae scraper, and the scraped suspended microalgae are collected in a collecting member, so that the concentration of suspended microalgae in the microalgae growth unit is below 0.4 g / L.

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